Means for protection against vesicants



MEANS FOR PROTECTION. AGAINST VESICANTS Ralph H. Bullard, Geneva, N.Y., and AIanRJGraIf and Vern McIntosh, Jr., Cleveland,hio, assignorsto TheLakeEr-ie ChemicalCompany, Cleveland, Ohio, :1 =corporafionof Ohio 1N0 Drawing. FiledvJune 19, 1940, Ser. No. 341,3 7

a 1 Claims. (31.117-121 Thisinvention deals with novel organic substances or compounds found suitable-as protective agents against vesicant gases especially when'they have been added towearing apparel of the-ordinary porous fabric type.

For a long time the need has been recognized for: a method of treating wearing apparel Which-wouldafiord protection against the vaporsofmustard gas and other vesicants and which would at the same time permit evaporation of moisture from thebody. Inthe warrof 1914-1918, military personnel assigned to thedecontaniination of areas which had been sprayed with' 'mustard gas were protected by water-proof clothing completely covering the body and impervious to bothair and moisture. Such garments became veryuncomfortable after short periods of wear since they interfered withthenornial respiration of the body through tithe pores oflthe skin. They could only be worn.for a brief. period of time without injury to .health andtthis period issaid a chemical substance must meet certain rigid requirements. Amongthese are (a) the ability to irnpregnate textiles such as wool and khaki in-such a manner that its protective effect will remain at a high degree of efliciency over long periods of time; (b) the chemical equivalent of the substance in terms of the amount of vesicant agent destroyed per pound of protective substance, .should be as high as possible; (0) it must be stable under ordinary temperatures, and in storage; (d) it must be stable under the action of sunlight and weather and (e) it must be non-irritating to the surface tissues of the human body.

Wehave ascertained by extended experiment that nu- 'merous examples of the general class of nitrogen chlorides forrexample chloramines, chlorarnides or chlorimides-compounds containing a chlorine atom attached to a nitrogen atom-possess reactivity to render vesicants including mustard gas innocuous and at'the same time are sufficiently stable to remain active when impregnated in clothing and subjected to normal wearing conditions.

. Such classes of nitrogen chlorides include the following:

(1) N-chloroacylarylamines, including monoand polyamino compounds, and derivatives of these compounds.

(2) N-chloracylalkylamines, -polyamines, and derivatives.

(3) Mono and di alkyl, aryl, and acyl derivatives of mono, di, trichlorinated ureas. Also alkylacylchloramino; arylchloramino, acylchloramino, and alkylchloramino derivatives.

(4) N-chloroimides of mono, di, and polybasic acids.

rates Patent (5 Quinone chlorimines, -dichlorimines,' and derivatives.

(6) Monoand di-chloroarylsulfonamides, and derivatives.

(7) N-dichloroarylamines, and derivatives.

(8) -Ring compounds containing an group. (9) 'Monoand dichloroamides.

(10) Halogenated triazines.

N or in which the chlorine will have the proper degree of stability and reactivity. Such compounds exist in each of the classes mentioned above.

Certain general considerations, exist in the selectionv of such compounds. .For example, in compounds with a phenyl radical attached to the nitrogen-chlorine .group, the chlorine atom has. a tendency to Wander into the nucleus, filling the o and p positions. This may be prevented by substituting groups in the'phenyl radical which will decrease its susceptibility to chlorination. Substituting one or more of the oand p hydrogenswith chlorine will increase stability towards molecular chlorination. If acyl or other groups beside the chlorine atom are attached to the nitrogen they affect the}reactivity of the chlorine and its rate of transfer into'the nucleus.

Among the chlorimines (containing the grouping =N-Cl) those compounds in which the nitrogen atom is double bonded to an aromatic carbon atom .seem more stable than those in which the nitrogen is double bonded to an aliphatic carbon atom, as in aldoand ketochlorimines.

Compounds containing two C=O groups attached to the NCl group are in general more stable than compounds containing one C=O group attached to the nitrogen. The monoand di-chlorarylsulfonamides are quite .stable in almost all instances.

Typical examples of stable nitrogen chlorides containing chlorine available as a protective against vesicants are N,N,2,2',4,4'-hexachlorodiphenylurea Cl 01 I Cl (I)I (11 l and N,N',3,3,5,5'-hexachloro-N,N diacetyl benzidine,

which are rather stable, apparently harmless and capable of rendering mustard gas innocuous.

Some derivatives of the above compounds are also satisfactory. For example other halogens or nitro or nitroso groups may be substituted in the phenyl nucleus of either compound while in the second compound formyl, propionyl, benzoyl, or other groups may replace the acetyl groups; or acetylchloramino groups may be substituted in the benzidine nuclei.

Similar variations suggest the classes of nitrogen chlorides tabulated above.

Melamine has long been recognized as a derivative of cyanamide as the triazine and may be represented by the formula C N (NH By replacement of from one to six of the hydrogen atoms by chlorine we have discovered that compounds may be produced which show that such highly chlorinated derivatives are superior to many other compounds in their stability, reactivity and efiiciency in circumstances where the chlorine must be available for entering into desired reactions. Such a product, sym-trichlormelamine has the following formula:

The alkyl or aryl or acyl derivatives, for example, the acetyl derivative, C N (NCl.COCH are also suitable sources of available chlorine for these purposes.

Several methods are known for making chloramines starting from acetanilides derivatives, urea derivatives, acid imides and arylsulfonchloramides by the use of sodium or calcium hypochlorite, bleaching powder or free chlorine. We have outlined our preferred method in our co-pending application filed June 19, 1940, Serial No. 341,386.

Among the substances outlined above are excellent sources for halogens, particularly chlorine, to be freed upon exposure to vesicant vapors, liquids and solids (for example mustard gas), and to render the latter innocuous. Considerable importance attaches however to the means by which this reaction can take place, that is, to the establishment of the proper physical and chemical circumstances for the reaction between the vesicant compound and the protective compound containing halogen. Our invention refers most particularly to the application of protective substances as outlined above to textiles and fabrics of various kinds so that these fabrics while remaining permeable will, when worn as clothing, prevent the vesicant substances from reaching the skin and will thus prevent or minimize injury of the skin tissues by the vesicant substance or substances.

The greater number of protective substances in the classification referred to above are insoluble in water, indeed, except under special circumstances, such solubility will be one of the criteria of the suitability of the substance as an impregnant for fabrics. Some of the substances are soluble in certain organic solvents, others are relatively insoluble.

Two general methods of applying the protective substance to the fabric are:

A. Dipping the fabric in, or spraying the fabric with a fluid consisting of a solid suspension of the protective substance and B. Dipping the fabric in or spraying the fabric with a.

fluid consisting of a solution of the protective substance in a suitable solvent.

If a solid suspension is used, the suspending medium. may be water or it may be an organic liquid, such as ben zene, monochlorbenzene, carbontetrachloride, etc. The primary requirements of the suspending medium are, of course, that it shall not react with the protective substance during the impregnation process and that its drying characteristics shall be such as to leave the solid protective substance in and on the fabric of the cloth in a suitable state of physical dispersion. It may be necessary or desirable to add certain auxiliary substances to the impregnating fluid in the form of emulsoids, suspensoids or solutes. The functions of these auxiliary substances may be to promote or maintain the physical dispersion of the protective substance; to bind the particles of the protective substance to the fabric; and/or to. promote the chemical reaction between the protective substance and the vesicant agent Which it is the purpose of the protective substance to destroy.

These auxiliary substances may also assist in maintaining, insofar as possible, the original appearance and feel of the cloth. As a result of experimentation, it has been found that white Russian mineral oil, which is a water white, odorless mineral oil, when added as an auxiliary substance to the impregnating fluid, acts as a binder to hold the protective substance on the cloth. It also assists in the maintenance of the natural appearance and feel of the cloth. It has also been observed that when such oil is used as an auxiliary substance, that the impregnated fabric resists penetration by the vapors of mustard gas for longer intervals than when it is not used under similar conditions in our tests. Various other oils and various waxes and resins, provided they do not adversely affect the stability or reactivity of the protective compound, may be used as auxiliary substances. We have successfully used Vaseline and a number of natural and synthetic commercial waxes. It is obvious that all compounds in these classes are not suitable as auxiliary substances.

As an example of a method of impregnating our protective substances on fabrics, we give the following:

Dry clean the fabric to be impregnated, removing dirt, grease, and other foreign matter. Prepare an impregnating bath by dissolving the protective compound in monochlorbenzene, filtering, adding white mineral oil as an auxiliary substance and bringing the solution to proper concentration. We have used, for example, 1 part of white mineral oil (auxiliary substance) to 2.75 parts of N,N',3,3',5,5' hexachloro N,N' diacetyl benzidine (protective compound) to 34 parts of monochlorbenzene (solvent). This bath is kept at 25 to 35 C. and a tendency toward cloudiness or incipient crystallization is prevented by warming and subsequently cooling. The fabric which has been cleaned, dried with hot air and left slightly warm, is immersed in the impregnating bath and stirred or agitated for one or two minutes, after which it is removed, drained and wrung out. The amount of wringing, or in other words, the amount of liquid left on the cloth, will determine the density of impregnation. If a heavier impregnation is desired, the proportion of protective substance to liquid solvent may be increased and/or the cloth may be wrung more lightly after immersion in the impregnating bath. It has been found that if the weight of protective substance impregnated in the cloth is approximately 12% of the original weight of the cloth, that (for the protective substances which we have tested and found to be suitable) the cloth will resist penetration by mustard gas in a satisfactory manner. After immersion in the impregnating bath and wringing out, the fabric is dried. Drying should not be too rapid or the impregnation may be markedly uneven. The treated fabric, after drying, may be stored until required. This mode of application is suitable for both outer garments and undergarments.

Another method of impregnating fabric is as follows:

The protective substance is brought (by grinding, if necessary) into a very fine state of subdivision. Together with suitable auxiliary substances the powdered protective substance is then worked into or blended into water to form a suspension. The fabric to be impregnated, free from dirt, grease or other foreign matter, is dipped in this suspension and thoroughly worked, by hand or mechanical means, under or above the surface of the liquid to promote distribution of the suspension between the cloth fibres. It is then removed from the suspension, wrung out to the degree desired and dried.

The invention contemplates the use of any one of the above catalogued protective compounds when carried on fibers of porous fabric. The nature of the fabric and the particular constitution of the protective substance may of course be varied in accordance with the scope of the invention as defined in the following claims.

What we claim is:

1. A vesicant protection means comprising benzidine in which amino hydrogen atoms have been displaced by chlorine and by at least one acyl radical.

2. A vesicant protection means comprising benzidine in which chlorine has displaced two hydrogen atoms in the amino groups and four hydrogen atoms in the nuclei.

3. A vesicant protection means comprising benzidine in which chlorine has displaced two hydrogen atoms in the amino groups and four hydrogen atoms in the nuclei and in which acetyl groups have displaced two aminohydrogen atoms.

4. A vesicant protection means comprising N,N' diacetyl, hexachlorobenzidine.

5. A vesicant protection means comprising a fabric impregnated with benzidine derivatives in which chlorine has displaced hydrogen atoms in the amino groups and in the nuclei.

6. A vesicant protection means comprising a fabric impregnated with benzidine derivatives in which chlorine has displaced hydrogen atoms in the amino groups and in the nuclei and in which acetyl groups have displaced two amino-hydrogen atoms.

7. A vesicant protection means comprising a fabric impregnated with N,N diacetyl hexachlorobenzidine.

References Cited in the file of this patent UNITED STATES PATENTS 255,040 Skinner Mar. 14, 1882 263,907 Homer Sept. 5, 1882 1,826,329 Stampe Oct. 6, 1931 1,949,781 Champlin Mar. 6, 1934 2,073,730 Champlin Mar. 9, 1937 2,184,883 Muskat Dec. 26, 1.939 2,184,886 Muskat Dec. 26, 1939 2,184,888 Muskat Dec. 26, 1939 2,185,864 Muskat Jan. 21, 1940 FOREIGN PATENTS 557,081 Germany 1932 588,131 Germany 1933 590,796 Germany 1934 496,734 Great Britain 1938 OTHER REFERENCES Chem. Weekblad, 33, pages 474-5.

Berichte, 34, pages 1073, 1074, 1078.

Vedder: Medical Aspects of Chemical Warfare, Williams, Williams, and Wilkins, Baltimore, 1925. 

5. A VESICANT PROTECTION MEANS COMPRISING A FABRIC IMPREGNATED WITH BENZIDINE DERIVATIVES IN WHICH CHLORINE HAS DISPLACED HYDROGEN ATOMS IN THE AMINO GROUPS AND IN THE NUCLEI.
 6. A VESICANT PROTECTION MEANS COMPRISING A FABRIC IMPREGNATED WITH BENZIDINE DERIVATIVES IN WHICH CHLORINE HAS DISPLACED HYDROGEN ATOMS IN THE AMINO GROUPS AND IN THE NUCLEI AND IN WHICH ACETYL GROUPS HAVE DISPLACED TWO AMINO-HYDROGEN ATOMS. 